shell - Bash script gets printed instead of being executed -

shell - Bash script gets printed instead of being executed -

this question similar one: http://serverfault.com/questions/342697/prevent-sudo-apt-get-etc-from-swallowing-pasted-input-to-stdin reply not satisfying (appending && each line of bash script not elegant) , not explain why users can paste/execute multiple subsequent apt-get install -y commands , others can't because stdout swollen next command.

i have script my_script.sh:

sudo apt-get install -y graphicsmagick sudo apt-get install -y libgraphicsmagick++1-dev ...

it can have 2 lines or more of sudo apt-get install stuff. libraries (graphicsmagick, etc.) doesn't matter, can library.

when re-create script , paste it's contents bash or execute this:

cat my_script.sh | sudo -i bash

then reason first line (graphicsmagick) gets executed , rest printed console. happens sudo apt-get install -y, other scripts, doesn't contain command behave normally.

if alter bash sh (which dash) expected behaviour:

cat my_script.sh | sudo -i sh

can explain why happens?

when answering, can please avoid questions/comments:

why doing way? piping bash not safe some other aspects not safe or hackish

i want know why bash doesn't work expect , sh does.

ps. i'm using ubuntu 14.04, sh dash can see here:

vagrant@vagrant-ubuntu-trusty-64:/tmp$ ls -l /bin/sh lrwxrwxrwx 1 root root 4 feb 19 2014 /bin/sh -> dash

bash , dash behave different when using -i flag. bash goes interactive mode when stdin not terminal. dash on other hand not go interactive mode, -i flag.

bash shell unix sh apt